Pulverulent mixtures containing low-emission nitrile rubbers

Abstract

Pulverulent mixtures containing at least one nitrite rubber and at least one release agent, which are characterized by a particular average particle diameter, are provided. These mixtures have particularly low emissions and are outstandingly suitable for producing materials and components for indoor applications.

What is claimed is: 
     
       1. A pulverulent mixture comprising:
 (1) at least one nitrile rubber which has repeating units of at least one α,β-unsaturated nitrite monomer and at least one conjugated diene monomer and has an emission ratio E according to the formula (I) of less than or equal to 
 
       
         
           
             
               
                 
                   
                     E 
                     = 
                     
                       
                         
                           [ 
                           
                             volatile 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             constituents 
                           
                           ] 
                         
                         
                           [ 
                           
                             Mooney 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             viscosity 
                           
                           ] 
                         
                       
                       × 
                       
                         
                           [ 
                           
                             Nitrile 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             content 
                           
                           ] 
                         
                         100 
                       
                     
                   
                 
                 
                   
                     ( 
                     I 
                     ) 
                   
                 
               
             
           
         
         0.25 mg/(kg*Mooney units),
 where
 [volatile constituents] is the concentration of volatile constituents in mg/kg of nitrite rubber determined by means of a TDS-GC/MS examination in accordance with the VDA 278 recommendation (09.2002 version) in the range from 28.4 minutes to 34.0 minutes, 
 [Mooney viscosity] is the Mooney viscosity ML 1+4 at 100° C. of the nitrite rubber determined in accordance with ASTM D 1646 and reported in Mooney units, and 
 [nitrite content] is the dimensionless content of the α,β-unsaturated nitrite in the nitrite rubber, determined in % by weight by the Kjeldahl method in accordance with DIN 53 625, and 
 
 
         (0) one or more release agents,
 wherein particles of the pulverulent mixture have an average particle diameter Da of 0.01 to 4 mm. 
 
       
     
     
       2. The pulverulent mixture according to  claim 1 , wherein the release agent(s) is/are selected from the group consisting of silica, calcium carbonate, silicate, PVC and fatty acid salts. 
     
     
       3. A process producing a pulverulent mixture according to  claim 1 , the process comprising contacting the nitrite rubber component with the one or more release agents. 
     
     
       4. The process for producing a pulverulent mixture according to  claim 3 , wherein the nitrile rubber component is produced by a process that comprises either a milling step or else a spray drying step, during the course of which contacting with the release agent(s) occurs in each case. 
     
     
       5. Composites comprising:
 (A) at least one pulverulent mixture according to the invention according to  claim 1 ; and 
 (B) one or more thermoplastic polymers. 
 
     
     
       6. The composites according to  claim 5 , wherein the thermoplastic polymers are selected from the group consisting of polyvinyl chloride, polyurethanes, polyamides, epoxy resins, phenolic resins, polypropylene, polyethylene, polyethylene-vinyl acetate and polystyrene. 
     
     
       7. The composites according to  claim 6 , wherein the thermoplastic polymers are selected from the group consisting of polyvinyl chloride, polyurethanes and polyamides. 
     
     
       8. The composites according to  claim 5 , wherein the components (A) and (B) are used in a weight ratio of (1-99):(99-1), preferably (10-60):(90-40), based on the sum of the components (A) and (B). 
     
     
       9. A process for producing the composites according to  claim 5 , the process comprising mixing the two components (A) and (B) with one another. 
     
     
       10. A method for producing articles of manufacture, the method comprising producing the articles the composites according to  claim 5 , wherein the articles of manufacture comprise components for use in automobile interiors. 
     
     
       11. Components based on composites according to  claim 5 . 
     
     
       12. The pulverulent mixture according to  claim 1 , wherein the particles have an average particle diameter Da of 0.2 mm to 1.5 mm. 
     
     
       13. The pulverulent mixture according to  claim 1 , wherein the particles have an average particle diameter Da of 0.08 mm to 0.12 mm. 
     
     
       14. The pulverulent mixture according to  claim 1 , wherein the nitrite rubber has an emission ratio E according to the general formula (I) of less than or equal to 0.20 mg/(kg*Mooney units).